Warm, windproof, water-resistant—the Nano Puff® Jacket uses incredibly lightweight and highly compressible 60-g PrimaLoft® Gold Insulation Eco 100% postconsumer recycled polyester. Had this for several years but I've moved away from a ski town, and it's time to move on. There is a very faint stain on the front (pictured--its barely visible). Such a good mid-layer.